Embolism is the event of lodging of an embolus (a detached intravascular mass) into a narrow vessel, which causes a blockage in a distant part of the body. Embolism can be classified as to whether it enters the circulation in arteries or veins. Arterial embolism can start in the heart or in large arteries, and can cause occlusion and/or infarction in any part of the body. Embolus lodging in the brain from either the heart or the carotid arteries can cause an ischemic stroke. Venous embolism, which forms in systemic veins, can lodge in the lungs after passing through the right side of the heart. This deleterious condition is known as pulmonary embolism.
Distal embolization can occur spontaneously or be induced by manipulation of the heart, large arteries, or veins, either in the setting of open surgery, or in the setting of endovascular manipulation such as balloon angioplasty or stenting.
Distal embolization can be prevented by pharmacological treatment (anti-coagulants). While effective, anticoagulants have the deleterious side effect of high bleeding risk, which may be severe or even life-threatening. In addition, many patients do not tolerate well anticoagulant medication and cannot enjoy the embolic protection that it may render.
Distal embolization may also be prevented or by using mechanical filtering devices (distal embolic protection devices), which are placed between the embolic source and the distal vasculature. However, prior and current devices fail to adequately address the problem, and in fact, in many circumstances, cause problems (e.g., become occluded, migrate from the implantation site, and the like).